Such a kit is notably intended for injecting fluid into a patient, for example in the field of oncology or during the injection of a contrast product into a patient, in order to achieve the taking of a medical image.
This image may be used for non-invasive evaluation of the characteristics of the vascular system of the patient, for example for performing an angiography by computer tomography, designated as “CT”.
In the latter case, it is necessary to inject very rapidly with a high flow rate, a contrast product into the vascular system of the patient, with which a sufficiently high concentration may be obtained in order to have sufficient contrast during the full scanning time which is of the order of 30 to 45 seconds.
In order to facilitate the injection of a contrast product at a high flow rate into the vascular system of the patient, the use of a kit of the aforementioned type is known, including a chamber implanted under the skin of the patient. The chamber defines an injection point in the patient, which is located away from the blood circulation conduit into which the product has to be injected. This avoids deteriorating the blood circulation conduit by repeated pricks through this conduit.
In a known way, such a chamber includes a hollow body obturated by a flexible septum and a conduit for evacuating liquid out of the hollow body. The discharge conduit protrudes from the hollow body as far as the injection point into the vascular system.
In order to inject the liquid into the patient, the practitioner connects the outlet of the liquid dispensing apparatus to the needle injection device. And he/she then introduces the needle of the device into the chamber through the septum. He/she then triggers injection of liquid from the injection apparatus through the injection device and the chamber.
In order to guarantee introduction of liquid at a very high flow rate, for example greater than 1 ml/s, it is necessary to substantially increase the pressure at the outlet of the injection apparatus. This outlet pressure may for example be greater than 18 bars.
Nevertheless, because of their design, the implantable chambers have a maximum pressure of use which is generally much lower than the pressure of the liquid delivered by the injection apparatus, for example equal to about 8 bars. In applications where the fluid is injected at a very high flow rate, there therefore exists a substantial risk that the chamber does not withstand the internal pressure of the fluid from the dispensing apparatus.
In order to limit the risk incurred by the patient, the American patent application US 2009/0227951 describes a kit in which the needle injection device has a substantial pressure loss of the order of about fifteen bars. Such an injection device therefore guarantees the safety of the patient, while providing a high pressure loss.
Such an injection device should however be designed specifically for high flow rate injections and cannot be used for other injections of products, notably at lower flow rates in which the pressure at the outlet of the injection apparatus is lower. This therefore increases the cost of the aforementioned kit and limits its possibilities of use.